
Access:
As specified in 3GPP TR 22.829, UxNB is able to connect to the 5G core network and operate as a BS, via a wireless backhaul link, and can bootstrap as a BS, from the core network's perspective. To do so, we assume that the UxNB is equipped with multiple antennas enabling directional patterns towards users [1]}.

Backhaul: The backhaul can be provided by a wireless gateway (e.g., a nearby TBS, TUAV, or satellite) or through an associated anchor, if it provides backhauling services. In the case of a wireless backhaul, integrated access and backhaul (IAB) can be leveraged [2]}, [1]}. Since 3GPP does not enforce any particular IAB implementation, radio access and backhauling can use different frequency bands or the same spectrum. The latter is possible since a UxNB supports directional antenna arrays to spatially separate the links.

Power: To reduce costs, we assume that the iTUAV is equipped with a small battery that enables short flight times to reach anchors and reconnect through a tether. Moreover, each iTUAV is equipped with a socket that allows it to attach a retractable tether from the anchor and that can be used simultaneously to power the motors in-flight and to recharge the battery.
This design suggests landing over the anchor to attach the iTUAV, thus causing service delays. Alternatively, the iTUAV can be equipped with a lightweight tether that is dropped vertically to the anchor rather than landing on it [4]}.

